Crystallization-Engineered Single-Crystal T-Nb₂O₅ Whiskers with Nearly 100% Exposed Vertical (001) Facets for Li-Ion Storage

Tailoring the crystalline structure and facet orientation of T-Nb₂O₅ anode electrodes is pivotal for optimizing the Li⁺ transport kinetics. Herein, a crystallization engineering strategy is employed to synthesize urchin-like T-Nb₂O₅ microspheres composed of single-crystalline whiskers growing along the (001) orientation. These whiskers are characterized by nearly 100% exposed vertical (001) facets that accelerate Li⁺ diffusion. Furthermore, the remaining N^3- expands the interlayer spacing, which optimizes Li⁺ transport pathways. Benefiting from these synergetic effects, abundant ion entry and exit sites with smooth ion transport channels promote the rapid Li⁺ diffusion in the T-Nb₂O₅ microspheres, delivering a high capacity and improving the rate performance (324 mAh g^-1 at 0.05 A g^-1, 87.5 mAh g^-1 at 5 A g^-1). This work presents a strategy of crystallization engineering for the preparation of fast-charging electrode materials and provides deep insights on the correspondence among morphology, lattice structure, and electrochemical performance.